drm/amd/display: Remove assert for odm transition case

Remove assert that will hit during odm transition case, since this is a
valid case.

Signed-off-by: Eric Bernstein <eric.bernstein@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>